Four-way, slide, selector valve



Nov. 28, 1950 T. c. HILL 2,531,511

FOUR-WAY, SLIDE, SELECTOR VALVE Filed Sept. 2'7, 1946 2 Sheets-Sheet l gwuem foa THO/VHS a H/L L Nov. 28, 1950 T. c. HILL FOUR-WAY, SLIDE, SELECTOR VALVE 2 Sheets-Sheet 2 Filed Sept. 27, 1946 awe/whorl" Patented Nov. 195i) mun-war, sLms, sanuoron VALVE Thomas 0. mu, Baltimore, Ma, minor to The Glen a corporation or Mary L. Martin Company, Middle River, Md.,

land

Application September 21, 1940, serial No. ceases is one so constructed and arranged that when it is inserted in a, hydraulic systemjthe' pressure supply line from the pump to the cylinder and the return line to the reservoir pass through the valve. The valve can control the flow of high pressure fluid to either end of the double acting cylinder and at the-same time control the flow of i0 fluid from the low pressure end of the cylinder to the reservoir.

For smooth operation of the hydraulic system,

the valve should include structure for metering the flow offluid through the ports upon opening and closingof the valve. The valve should have structure to provide for proper -pressure balance for ease of operation of the valve itself. To insure no lag in the hydraulic system, the ports in the valve should be adequate for the flow of fluid necessary to operate the hydraulic cylinder. As in most highpressure systems, the valve is made fluid-tight by resilient elastic gaskets or seals. It is most desirable to arrange the seals in the valve to render the valve fluid-tight with a minimum of 2a stress on the seals, that is, prevent leakage or seepage externally oi the valve, without subjecting the seals to the stress of the high pressure fluid. 1

In some hydraulic systems employing selector valves, ii internal leakage or seepage should develop, the high pressure fluid will escape to either line connected to the double acting hydraulic cylinder and cause the cylinder strut to creep. This internal leakage, may cause serious malfunction of the apparatus to which the hydraulic cylinder is attached. Such a hydraulic cylinder is commonly used to extend and retract moving parts on an airplane. For example, the passenger ramps 40 on commercial airplanes are so extended from the fuselage, and the flaps also are extended by such cylinders to positions of high lift and high drag. It can readily be seen that creepage oi the cylinder, due to internal leakage in the valve, could have serious effects if such components were extended in flight.

An object or this invention is the provision of a selector valve that provides the proper pressure balance to insure ease of operation of the valve. 5

Another object of this invention is the provision of simple structure that provides for double passages. I

2 Claims. (01. lei-4am Another object of this invention is the provision of a selector valve that. will have no resilient gasket or seals subjected to high pressure fluid. Another object of this invention is the provision of a selector valve structure in which internal leakage cannot cause creepage of the hydraulic cylinders in the equipment that it is intended to control.

Another object of this invention is the provision of a selector valve in which the return low pressure passages are arranged adjacent the outside walls so that the seals are subjected to low pressure fluid only.

A further object or this invention is the arrangement of passages in a selector valve so that any leakage or seepage of fluid from the high pressure path throughthe valve will flow directly into the return path through the valve and prevent the accumulation of high pressure fluid leakage.

Further and other objects will become apparent from the descriptionoi the accompanyingdrawings which form a part of this disclosure and in which like numerals refer to like parts.

In the drawings: Figure 1 is a typical installation showing the use of the tour-way selector valve.

Figure 2 is a sectional view taken on the line 2-2 of Figure 3.

Figure 3 is a plan view of the valve.

Figure 4 is a section taken on the line 4-4 of Figure 2.

The valve generally indicated as I in Figure 1 is a four-way selector valve that directs fluid uninadvertent motion of the cylinder strut, due to der pressure to either side of the piston in the conventional double acting hydraulic cylinder, generally indicated as 2. Fluid pressure in line 3 will cause the strut l of the hydraulic cylinder to be extended and fluid pressure in line 5 will cause the strut to be retracted within the cylinder. When line 3 acts as a pressure line to conduct hydraulic fluid to cylinder 2, line 5 acts as a return line. Hydraulic fluid is stored in reservoir 6. Pump 1 is any conventional high pressure hydraulic pump that delivers fluid to line 8 at a relatively high'pressure. In the system in which this selector valve is intended to be used, by high pressure is meant a normal hydraulic pressure of about 1500 lbs. per sq. inch. Line Q serves as a high pressure line delivering hydraulic fluid to the selector valve. Line 9 acts as a return line from the valve to the reservoir. A vent III to the atmosphere maintains the reservoir, and therefore line 9, under substantially atmospheric pressure conditions. A conventional pressure relief valve I is connected between lines 3 and 3 to provide a by-pas's for the pump when the valve is in its neutral position. when valve stem II is moved to the right or to the left, the fluid pressure from line 3 will be caused to enter lines 3 or 5, thus causing the'strut 4 of hydraulic cylinder 2 to move to either the right or to the left. Upon mosure balance within the valve, double porting and metered flow, and an arrangement of fluid pressure seals that are never subjected to the high presssure fluid flowing through the valve, but only to the return line pressure for all conditions of operations. Furthermore, any high pressurefluid due to leakage or seepage within the valve will flow into the passages through the valve that are open to the return line and therefore pressure cannot accumulate to aflect the seals. Valve I consists of a housing having a bore I2 fluid-tight fit. If leakage or seepage of fluid should take place past flanges 24 or 21, the fluid seepage or leakage will be in the return line system and a pressure cannot be developed in chambers I3 or 23 to which seals 3| and 32 might be subjected.

Figure 4 is a section through port It and is typical of ports I6 and I1. It-will be noted that port I6 is formed by drilling a hole in valve I that extends through bore I2 and into the valve housing on the opposite side of bore I2. The intersections of hole It and bore I2 form two ports. That is, due to the undercut portion 23 of valve I3, fluid communication is afforded between both intersections of hole I6 and bore I2 which effectively amounts to double porting for the flow of fluid past flange 21. The intersection of the two cylindrical openings, coupled with the action of flange 21, aflords two metered flow therethrough, into which slide valve I3 is placed.

Port I4 communicates with bore I2 and affords a connection for the high pressure line 3. Port I5 is in communication with bore I2 and affords a connection for return line 3. Ports I6 and I1 act as connections for pressure and return lines alternatively from the valve to the hydraulic cylinder. The end It of valve I3 is adapted to be connected to an actuating mechanism. Valve I3 is formed from a rod or cylinder of substantially the same diameter as bore I2. It is undercut at I 3, 26, 2|, 22 and 23 to provide annular passages for fluid between adjacent ports and also to provide flanges 24, 25, 26 and 21. These flanges are so spaced along the valve that flanges 24 and 21 extend between ports I6 and I1 so that in the neutral position of the valve no fluid will flow through either ports I6 or I1. Flanges 25 and 26 are so spaced relative to flanges 24 and 21 and the width of ports I6 and I1 that they will close communication between either port I6 or I1 and the return system when the valve is moved to the right or to the left to permit the passage of I high pressure fluid to ports I6 and I1. Flanges 25 and 26 are so spaced that ports I6 and I1 are in communication with the return system when the valve is in the neutral position. Passage 23 is formed through the center of valve I3 and ports 29 and 36 afford communication between the undercut portions of the valve and passage 23. Through these ports and passages it will be seen that when the valve is in the neutral position, ports I6 and I1 are in communication with the return port I5. The function of flanges 24, 25,

in the return line system. The flanges engage the walls of the bore with a sliding but relatively apertures for the fluid past flange 21. That is, the flange is opened slightly upon initial motion and the subsequent flow through the port depends upon the metering action of the port. Due to the bore of port I6 extending on each side of bore I2 affording double porting, double metering of the flow is also effected. By this same structure, a pressure balance for the valve is achieved, that is, due to the annular passage 26 around the valve and the porting of the valve in two diametrically opposite places, the valve is not sub- Jected to an unbalance in pressure, but rather achieves a pressure balance which contributes.

to the smooth operation of the valve.

The spacing of flanges 24 and 25 is determined edge of each flange is the important operative portion of this structure. Having the undercut portion 22 form the two flanges, however, serves two additional important purposes, first, weight reduction is effected by removing excess metal which is very important in aircraft applications, and second, cutting down the area in contact with the wall of bore I2 of the two flanges to a minimum, facilitates making a lapped flt of the valve in the bore for fluid pressure sealing.

The threaded sleeve 33 on the valve housing supports a member 34 in which is located the selfcentering mechanism for valve I3. Housing 34 has retaining washers 35 and 36 between which extends compression spring 31. Washers 35 and 36 slide on shaft 38 which is secured in the end of valve I3 in passage 28. Compression spring 31 will tend to hold washers 35 and 36 against stops 33 and 46. Nuts 4i and 42 locate the assembly of washers 36 and 36 between stops 33 and 40. It will be seen that if the valve is moved to the left, washer 35 will compress spring 31 which will tend to return washer 35 to a position against stop 33. Motion of the valve to the right will cause spring 31 to be compressed by washer 36 which will be returned to the left by the spring to seat against stop 40. This self-centering device housed in member 34 causes the valve to be returned axially to a predetermined position. By adjusting the axial position of member 34 on sleeve 33, the neutral position of the valve I3 may be adjusted relative to ports I6 and I1. Lock nut 43 maintains the adjustment of the neutral position of the valve. Member 44 affords a protective cover for the self-centering mechanism.

The operation of the valve can be readily fol- 7s lowed on Figures 1 and 2. Fluid under pressure 5. will enter port II and fill chamber 2 I. If leakage or seepage takes place past flanges 24 or 21, the fluid pressure will be dissipated because the portion of the system into which it leak is at all times connected to the return line through port I5. If the valve is moved to the right, fluid pressure will flow from chamber 2| through port I! and line to retract strut l in cylinder 2. Before flange 24 will permit fluid to passfrom chamber 2| to port II, flange 25 will have closed communication between port I! and chamber 23. By this same motion, spring 31 will have been compressed by washer 36. When the displacing force on valve I3 is removed, spring 31 will return washer 36 and valve l3 to a predetermined neutral position. The return path for the fluid in the cylinder will be provided through line 3, port l6, chamber 19, port 29, passage 26, port 30, port l5 and line 9. Similar pressure and return lines will be provided when the valve is displaced to the left for the reverse action of the hydraulic cylinder.

It is to be understood that certain changes, alterations, modification and substitutions can be made without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. A selector valve for use in a hydraulic-system, comprising a valve body having a substantially smooth, cylindrical bore, a valve member axially slidable within said bore, outlet ports in said body affording connections for pressure and return lines from said valve to a hydraulic cylinder, each outlet-port extending from the exterior of said body and intersecting said bore at one side thereof and extending through into the opposite wall thereof, a pressure port communicating with d said bore for supplying pressure fluid thereto, and a return port communicating with said bore for discharging fluid therefrom, said valve member comprising a cylindrical member of substan- 4 I tion'to close communication between said portions and said return flow chamber before said tially the same diameterv as said bore forming therewith a sliding fit, said valve member being undercut to provide a plurality of axially spaced flanges, forming annular chambers therebetween including a center chamber spanning said pressure port and a pair of return chambers spaced axially therefrom and communicating with said return port, said outlet ports being located along said bore on each side of said pressure port, said flanges including a flange on said valve member adjacent each outlet port to prevent the flow of fluid from said high pressure chamber to either outlet port when the valve is in neutral position, and a flange on said valve member adjacent each outlet port and spaced from said first mentioned flange to afford open communication between the portions of said outlet port on opposite sides of said bore and to permit communication between said portions of said outlet port and the adjacent return chamber when the valve member is in the neutral position and arranged upon axial displacement of said member in one direction to close communication between said outlet port and said chamber before said first mentioned flange moves to a position to pass fluid pressure from said pressure chamber to said outlet port, the other outlet port upon such displacement of 6 said member being maintained in communication with said return chambers.

'2. A selector valve for use in a hydraulic system, comprising a valve body havin a substantially smooth cylindrical bore, a valve member axially. slidable within. said bore, outlet ports in said body affording connections for pressure and return lines from said valve to a hydraulic cylinder, each outlet port extending from the exterior of said body and intersecting said bore at one side thereof and extending through into the opposite wall thereof, a pressure port communicating with said bore for supplying pressure fluid thereto, and a return port communicating with said bore for discharging fluid therefrom, said valve member comprising a hollow cylindrical member of substantially the same diameter as said bore formin therewith a sliding fit, said valve member being undercut to provide a plurality of axially spaced flanges forming annular chambers therebetween including a center chamber spanning said pressure port forming a fluid pressure chamber and a pair of return flow chambers spaced axially therefrom, said outlet ports being located along said bore on each side of said pressure port, said return flow chambers being interconnected through said hollow cylindrical member and being in open communication with said return port, said flanges including a flange on said valve member adjacent each outlet port to prevent the flow of fluid from said high pressure chamber to either outlet port when the valve member is in neutral position, and a second flange adjacent each outlet port and spaced from said first mentioned flange to afford open communication between the portions of said outlet port on opposite sides of said bore and between said portions and the adjacent return flow cham-- ber when the valve is neutral and arranged upon axial displacement of said member in one direcflrst mentioned flange moves to a position to pass The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain Mar. 10, 1896 

